2016-02-06 09:37:19 +00:00
|
|
|
# sql/annotation.py
|
2016-02-22 11:13:36 +00:00
|
|
|
# Copyright (C) 2005-2016 the SQLAlchemy authors and contributors
|
2016-02-06 09:37:19 +00:00
|
|
|
# <see AUTHORS file>
|
|
|
|
#
|
|
|
|
# This module is part of SQLAlchemy and is released under
|
|
|
|
# the MIT License: http://www.opensource.org/licenses/mit-license.php
|
|
|
|
|
|
|
|
"""The :class:`.Annotated` class and related routines; creates hash-equivalent
|
|
|
|
copies of SQL constructs which contain context-specific markers and
|
|
|
|
associations.
|
|
|
|
|
|
|
|
"""
|
|
|
|
|
|
|
|
from .. import util
|
|
|
|
from . import operators
|
|
|
|
|
|
|
|
|
|
|
|
class Annotated(object):
|
|
|
|
"""clones a ClauseElement and applies an 'annotations' dictionary.
|
|
|
|
|
|
|
|
Unlike regular clones, this clone also mimics __hash__() and
|
|
|
|
__cmp__() of the original element so that it takes its place
|
|
|
|
in hashed collections.
|
|
|
|
|
|
|
|
A reference to the original element is maintained, for the important
|
|
|
|
reason of keeping its hash value current. When GC'ed, the
|
|
|
|
hash value may be reused, causing conflicts.
|
|
|
|
|
|
|
|
"""
|
|
|
|
|
|
|
|
def __new__(cls, *args):
|
|
|
|
if not args:
|
|
|
|
# clone constructor
|
|
|
|
return object.__new__(cls)
|
|
|
|
else:
|
|
|
|
element, values = args
|
|
|
|
# pull appropriate subclass from registry of annotated
|
|
|
|
# classes
|
|
|
|
try:
|
|
|
|
cls = annotated_classes[element.__class__]
|
|
|
|
except KeyError:
|
|
|
|
cls = _new_annotation_type(element.__class__, cls)
|
|
|
|
return object.__new__(cls)
|
|
|
|
|
|
|
|
def __init__(self, element, values):
|
|
|
|
self.__dict__ = element.__dict__.copy()
|
|
|
|
self.__element = element
|
|
|
|
self._annotations = values
|
2016-02-22 11:13:36 +00:00
|
|
|
self._hash = hash(element)
|
2016-02-06 09:37:19 +00:00
|
|
|
|
|
|
|
def _annotate(self, values):
|
|
|
|
_values = self._annotations.copy()
|
|
|
|
_values.update(values)
|
|
|
|
return self._with_annotations(_values)
|
|
|
|
|
|
|
|
def _with_annotations(self, values):
|
|
|
|
clone = self.__class__.__new__(self.__class__)
|
|
|
|
clone.__dict__ = self.__dict__.copy()
|
|
|
|
clone._annotations = values
|
|
|
|
return clone
|
|
|
|
|
|
|
|
def _deannotate(self, values=None, clone=True):
|
|
|
|
if values is None:
|
|
|
|
return self.__element
|
|
|
|
else:
|
|
|
|
_values = self._annotations.copy()
|
|
|
|
for v in values:
|
|
|
|
_values.pop(v, None)
|
|
|
|
return self._with_annotations(_values)
|
|
|
|
|
|
|
|
def _compiler_dispatch(self, visitor, **kw):
|
|
|
|
return self.__element.__class__._compiler_dispatch(
|
|
|
|
self, visitor, **kw)
|
|
|
|
|
|
|
|
@property
|
|
|
|
def _constructor(self):
|
|
|
|
return self.__element._constructor
|
|
|
|
|
|
|
|
def _clone(self):
|
|
|
|
clone = self.__element._clone()
|
|
|
|
if clone is self.__element:
|
|
|
|
# detect immutable, don't change anything
|
|
|
|
return self
|
|
|
|
else:
|
|
|
|
# update the clone with any changes that have occurred
|
|
|
|
# to this object's __dict__.
|
|
|
|
clone.__dict__.update(self.__dict__)
|
|
|
|
return self.__class__(clone, self._annotations)
|
|
|
|
|
|
|
|
def __hash__(self):
|
2016-02-22 11:13:36 +00:00
|
|
|
return self._hash
|
2016-02-06 09:37:19 +00:00
|
|
|
|
|
|
|
def __eq__(self, other):
|
|
|
|
if isinstance(self.__element, operators.ColumnOperators):
|
|
|
|
return self.__element.__class__.__eq__(self, other)
|
|
|
|
else:
|
|
|
|
return hash(other) == hash(self)
|
|
|
|
|
|
|
|
|
|
|
|
# hard-generate Annotated subclasses. this technique
|
|
|
|
# is used instead of on-the-fly types (i.e. type.__new__())
|
|
|
|
# so that the resulting objects are pickleable.
|
|
|
|
annotated_classes = {}
|
|
|
|
|
|
|
|
|
|
|
|
def _deep_annotate(element, annotations, exclude=None):
|
|
|
|
"""Deep copy the given ClauseElement, annotating each element
|
|
|
|
with the given annotations dictionary.
|
|
|
|
|
|
|
|
Elements within the exclude collection will be cloned but not annotated.
|
|
|
|
|
|
|
|
"""
|
|
|
|
def clone(elem):
|
|
|
|
if exclude and \
|
|
|
|
hasattr(elem, 'proxy_set') and \
|
|
|
|
elem.proxy_set.intersection(exclude):
|
|
|
|
newelem = elem._clone()
|
|
|
|
elif annotations != elem._annotations:
|
|
|
|
newelem = elem._annotate(annotations)
|
|
|
|
else:
|
|
|
|
newelem = elem
|
|
|
|
newelem._copy_internals(clone=clone)
|
|
|
|
return newelem
|
|
|
|
|
|
|
|
if element is not None:
|
|
|
|
element = clone(element)
|
|
|
|
return element
|
|
|
|
|
|
|
|
|
|
|
|
def _deep_deannotate(element, values=None):
|
|
|
|
"""Deep copy the given element, removing annotations."""
|
|
|
|
|
|
|
|
cloned = util.column_dict()
|
|
|
|
|
|
|
|
def clone(elem):
|
|
|
|
# if a values dict is given,
|
|
|
|
# the elem must be cloned each time it appears,
|
|
|
|
# as there may be different annotations in source
|
|
|
|
# elements that are remaining. if totally
|
|
|
|
# removing all annotations, can assume the same
|
|
|
|
# slate...
|
|
|
|
if values or elem not in cloned:
|
|
|
|
newelem = elem._deannotate(values=values, clone=True)
|
|
|
|
newelem._copy_internals(clone=clone)
|
|
|
|
if not values:
|
|
|
|
cloned[elem] = newelem
|
|
|
|
return newelem
|
|
|
|
else:
|
|
|
|
return cloned[elem]
|
|
|
|
|
|
|
|
if element is not None:
|
|
|
|
element = clone(element)
|
|
|
|
return element
|
|
|
|
|
|
|
|
|
|
|
|
def _shallow_annotate(element, annotations):
|
|
|
|
"""Annotate the given ClauseElement and copy its internals so that
|
|
|
|
internal objects refer to the new annotated object.
|
|
|
|
|
|
|
|
Basically used to apply a "dont traverse" annotation to a
|
|
|
|
selectable, without digging throughout the whole
|
|
|
|
structure wasting time.
|
|
|
|
"""
|
|
|
|
element = element._annotate(annotations)
|
|
|
|
element._copy_internals()
|
|
|
|
return element
|
|
|
|
|
|
|
|
|
|
|
|
def _new_annotation_type(cls, base_cls):
|
|
|
|
if issubclass(cls, Annotated):
|
|
|
|
return cls
|
|
|
|
elif cls in annotated_classes:
|
|
|
|
return annotated_classes[cls]
|
|
|
|
|
|
|
|
for super_ in cls.__mro__:
|
|
|
|
# check if an Annotated subclass more specific than
|
|
|
|
# the given base_cls is already registered, such
|
|
|
|
# as AnnotatedColumnElement.
|
|
|
|
if super_ in annotated_classes:
|
|
|
|
base_cls = annotated_classes[super_]
|
|
|
|
break
|
|
|
|
|
|
|
|
annotated_classes[cls] = anno_cls = type(
|
|
|
|
"Annotated%s" % cls.__name__,
|
|
|
|
(base_cls, cls), {})
|
|
|
|
globals()["Annotated%s" % cls.__name__] = anno_cls
|
|
|
|
return anno_cls
|
|
|
|
|
|
|
|
|
|
|
|
def _prepare_annotations(target_hierarchy, base_cls):
|
|
|
|
stack = [target_hierarchy]
|
|
|
|
while stack:
|
|
|
|
cls = stack.pop()
|
|
|
|
stack.extend(cls.__subclasses__())
|
|
|
|
|
|
|
|
_new_annotation_type(cls, base_cls)
|